Need help creating my first keygen for a CrackMe

[Lukesc1993]

So I just cracked my first CrackMe and found out how the program computes the registration number and now I wanna write a keygen for it.

 

What program should I use to write the keygen and could anyine get me started on the code?

 

The algorithm the CrackMe uses to create the correct keygen is:

 

Get hex value of each letter in username

Add each letter in hex together

Multiply the value by 539

Output as decimal

 

Thanks to anyone who can help

[GIV]

VB .NET 2010

Public Class frmKeygen

    Private name As String = ""

    Dim character As Long = 0

    Private sum As Integer
    Private Sub txtInput_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtInput.TextChanged

        name = txtInput.Text

        Try

            For i = 0 To name.Length - 1

                character = character + Asc(name.Substring(i, 1))

            Next

            character = character * 539

            txtOutput.Text = character.ToString

        Catch ex As Exception

            MessageBox.Show("The result of multiplication is too high.", "Try less characters for the name.", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)

        End Try
    End Sub

End Class

Project.7z

Keygen.7z

[SiSC0]

C# .Net 3.5 - Console App - compile with SharpDevelop/VisualStudio/MonoDevelop/...

using System;

using System.IO;

using System.Linq;

using System.Reflection;
namespace Keygen

{

	class Program

	{

		static void Main( string[] args )

		{

			if( args.Length == 0 )

			{

				string thisExe = Path.GetFileName( Assembly.GetExecutingAssembly().GetName().Name );

				Console.WriteLine( "Use {0}.exe USERNAME", thisExe );

				return;

			}
			// first prog argument

			string username = args[ 0 ];
			// call/invoke Generate-Method

			decimal key = Generate( username );
			// show result, Output as decimal

			Console.WriteLine( "Key: '{0}'", key );

		}
		// easy to understand Method

		static decimal Generate( string username )

		{

			decimal result = 0;
			//Get hex value of each letter in username

			foreach( char letter in username )

			{

				//Add each letter in hex together

				result = result + (byte)letter;

			}
			//Multiply the value by 539

			result = result * 539;
			return result;

		}
		// pro variant

		static decimal ProGenerate( string username )

		{

			return username.Aggregate<char, decimal>( 0, ( current, letter ) => current + (byte)letter ) * 539;

		}

	}

}

[XorRanger]

Howdy.
Did Someone Forget other none .NET Languages?

 

Here is one for Delphi 7 (this is just the function that generates the key)

function MakeMyKey(UserName: string): string;var  intCounter, intHolder: Integer;  strFinalKey: string;begin  if (Length(UserName) < 1) then  begin    ShowMessage('Hey Cutie, Don' + 't be ' + 'shy :(' + sLineBreak +      'Please give me a Name');  end  else  begin    intHolder := 0;    for intCounter := 1 to (Length(UserName)) do    begin      intHolder := intHolder + Ord(UserName[intCounter]);    end;    strFinalKey := IntToStr(intHolder * 539);    Form1.edtSerial.Text := strFinalKey;  end;end;

Attached is the Keygen and its Full Source.

 

Lukesc1993 Keygen.zipLukesc1993 Src.zip

[GIV]

Howdy.

Did Someone Forget other none .NET Languages?

 

Did you mean this?

#include <iostream>#include <string>using namespace std;int main(){    int suma, lungime;	string nume;	cout << "Simple translation to C++ by GIV\n";	cout << "Please enter your name: "<<endl;    cin >> nume;    lungime = nume.length();	suma = 0;for (unsigned int i = 0; i < nume.size(); i++){     suma += nume[i];}cout << "The final calculus is:"<<endl;		cout << suma*539 << endl;     system("pause");    return 0;}

C++.7z

[Office Jesus]

Did someone forget about the non-high-level languages?

	Generate proc hWnd:HWND
		invoke	        GetDlgItemText, hWnd, IDC_NAME, addr NameBuffer, 17   ; Cap name length to 17

		mov		edi,offset NameBuffer

		invoke	        lstrlen,edi

		mov		esi,eax

		xor		ecx,ecx

		xor		eax,eax
		cmp		esi, 01h   ; Jump if no name entered

		jl		BADERROR
		xor		eax, eax

		xor		edx, edx
		@@:
			mov		dl, byte ptr [NameBuffer + ecx]

			add		eax, edx
			inc 	        ecx

			cmp		ecx, esi

			jnz		@b
		mov		ecx, 21Bh    ; 21Bh = 539d

		mul		ecx
		invoke	        wsprintf, addr SerialBuffer, addr FormatControl, eax

		invoke	        SetDlgItemText, hWnd, IDC_SERIAL, addr SerialBuffer
	BADERROR:
		xor		eax, eax

		ret
	Generate endp

Lukesc1993.zip

Edited November 9, 2014 by Office Jesus

[Levis]

 Did someone forget about script language? :worthy:

username = raw_input('Name -->')

serial = 0

for i in username:

	serial+=ord(i)

serial*=539

print serial

keygen.py.tar.gz

Edited November 14, 2014 by Levis

[ChOoKi]

So many options to choose from

[dstn]

Why not AutoIT? lol

#include <MsgBoxConstants.au3>
Example()

Func Example()

    Local $i, $output

	Local $Input = InputBox("Input","", "", "")
	For $i=0 to StringLen($input)

		$output = $output + Asc(StringMid($input,$i,1))

	Next
	$output = $output * 539
    MsgBox($MB_SYSTEMMODAL, "", $output)
EndFunc   ;==>Example

[sama]

I am to late.

No new code from my side

only a bit shorter ASM code of Office Jesus

Generate proc hWnd:HWND
	invoke	GetDlgItemText, hWnd, IDC_NAME, addr NameBuffer, 17   ; Cap name length to 17

	.if 	eax

		lea	edi, NameBuffer

		xor	eax,eax

		and 	edx,0

		.repeat	

			mov	dl,byte ptr [edi]

			add	eax, edx	

			inc 	edi

		.until byte ptr[edi] == 0

		imul	eax,eax,21Bh

	invoke	wsprintf, addr SerialBuffer, addr FormatControl, eax

	invoke	SetDlgItemText, hWnd, IDC_KEY, addr SerialBuffer

	.endif 
	ret
Generate endp

of course it can be done shorter.

(btw. i was to lazy, so i used OfficeJesus own code snippet.)

 

[Nucleus]

@Lukesc1993 Crackme name?